https://www.callendales.com/contact.html
I've got to get on my other computer to look up the FB details, I'm pretty sure it was the last build before the most recent one. Looking on the site, I see I used an Iframe to hold the form, it's on SDrive.
The iframe markup points to http not https:
<div id="framecenter"><iframe name="lets-talk" marginWidth=0 marginHeight=0 src="http://www.callie.coffeecup.com/forms/lets-talk" frameBorder=0 width=100% height=711px scrolling=no></iframe></div>
</div>
On S-Drive we do not offer SSL services so you are going to get an alert there because the iframe markup is calling something over http.